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CLEARANCE: Top Secret

The fuel requirement isn't that terrible -- I recall a figure of 8 gallons per shot a few years ago. Compared to the usual consumption of the ship's engines, that's not much. Radar has a much worse impact because it's consumption is continuous -- railguns are pulsed and the extra power to charge the pulse power generators is required only for short periods.

CLEARANCE: Top Secret

8 gallons of diesel is 26kg (57 lbs) which is about the same weight as a full propellant charge for a six inch (155mm) gun. The EX-175 high energy propellent cartridge for the 127mm weighes in at 18kg (41 lbs). So when one factors in savings in magazine space, fittings and protection compared to fuel bunkerage its about shot per shot weight equal. Plus of course the rail gun is far more effective and its burning the same fuel that creates the same electricity that can be used to turn the propeller, run the air conditioning or download emails.

CLEARANCE: Top Secret

Yes, it's a fairly heavy weight of fuel in absolute terms.
But let's let's look at it in relative terms. Propulsion fuel burn on a DDG-51 would be no less than about 25,000 gallons per day (even at low-speed cruise). Assuming a 600-round magazine (similar to conventional 127mm gun magazines and significantly larger than the DDG-1000's AGS magazines) even 8 gallons per round only eats up 4,800 gallons, which is a small fraction of one day's fuel use. That might not be a huge savings over the weight of separate propellant, but it sure is a logistical simplification, as Abraham notes. Being able to replenish gun propellant witha simple alongside connected refuelling rather than having to manhandle the charges below in a separate evolution is a major step forward.

And that 8-gallon figure may be a high estimate. I'm seeing one Navy-sourced article talking about 3 gallons per shot for a 64-MJ railgun projectile. That makes the total fuel use for a reasonable railgun magazine less than two hour's steaming at battlegroup speeds.

Actually, there are no gas turbines on thse ships. JHSV has four disel engines and reduction gears driving water jets for propulsion. They have four separate 600 kW diesel generators for ship-service and hotel loads, but that's not terribly large as these things go. (The generators on combatants are ~2.5 MW each).

I'd expect power generation for the railgun testbed to be a standalone system.

CLEARANCE: Top Secret

For the first test of the LaWS laser weapon at sea they just parked the laser turret and a diesel generator on the fantail of a destroyer. And the upcoming Ponce LaWS deployment will be similar. It appears this test (or series of tests) will be along similar lines. The weapon will be parked on the JHSV helipad and the generators will either be rolled onto the cargo deck or parked next to the weapon up top.

sferrin said:

Triton said:

bobbymike said:

The Navy is planning an at-sea demonstration with an electromagnetic railgun on board a Joint High Speed Vessel sometime in fiscal year 2016,...

They have both produced prototypes, Navy language is a little murky but it seems they intend to put both of the recent generation at sea in turn. BAE is building a new prototype with an automated loading mechanism after winning a down-elect last year. GA will compete with BAE again for the first prototype of a fully realized railgun weapon system for sea testing later this decade.

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Has there been any consideration for the railgun firing a beehive / grapeshot / flechette type round? Launched at an antiship weapon like the Chinese DF-21D, a flechette round would inflict serious damage on the warhead.

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Has there been any consideration for the railgun firing a beehive / grapeshot / flechette type round? Launched at an antiship weapon like the Chinese DF-21D, a flechette round would inflict serious damage on the warhead.

CLEARANCE: Above Top Secret

May 2, 2014
A draft House bill envisions the Missile Defense Agency assuming management from the Navy of a project to develop an electromagnetic rail gun. The House Armed Services Subcommittee on Strategic Forces in its mark-up of yearly defense authorization legislation noted the promise of the technology as a "more affordable air and missile defense" alternative, Inside Defense reported on Thursday. The legislation includes a directive for the Missile Defense Agency to work with the Pentagon's Strategic Capabilities Office to draft a report by mid-November that details a testing strategy for determining the "suitability of this [electromagnetic rail gun] technology for transfer to MDA for further development activity." The subcommittee said the Missile Defense Agency, with its special authority to speed along the acquisition process, was in a unique position to move forward the work done thus far by the Navy and the Strategic Capabilities Office. The Missile Defense Agency has already singled out the rail gun as a "priority" technology in light of its possibilities as a comparatively reasonably priced antimissile technology for use against theater-level ballistic missile threats. The rail gun is operated by an energy pulse instead of explosive fuel and is envisioned for use against a large number of targets, including cruise and ballistic missiles, and warships.

CLEARANCE: Above Top Secret

Thing I often notice is how *boring* real-life advanced weapons look compared to their sci-fi equivalents. The actual railgun looks pretty much like some pipe with some fat fittings, not like what sci-fi tells us a railgun is supposed to look like:

"Robert Gates, is that you??" sublight

The article in the link said the navy may implement the gun into their ship the following year after the test, which date at 2017. That sounds a little too good to be true, if not a lot. Can anyone verify that?

I really should change my personal text

The article in the link said the navy may implement the gun into their ship the following year after the test, which date at 2017. That sounds a little too good to be true, if not a lot. Can anyone verify that?

I really should change my personal text

The article in the link said the navy may implement the gun into their ship the following year after the test, which date at 2017. That sounds a little too good to be true, if not a lot. Can anyone verify that?

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I expect that we'd be looking at something similar to the deployment of a Laser Weapon System prototype on USS Ponce -- a single system, still more or less in a test configuration, fitted on a forward-deployed ship.

CLEARANCE: Top Secret

I expect that we'd be looking at something similar to the deployment of a Laser Weapon System prototype on USS Ponce -- a single system, still more or less in a test configuration, fitted on a forward-deployed ship.

Essentially yes. Instead of Ponce they're going to use a JHSV, not the least reason being that the JHSV has a big vehicle deck onto which generators and capacitors for the gun may be loaded. A "proof of concept" deployment.

WASHINGTON, 30 July 2014. U.S. Navy hypervelocity weapons experts needed powerful and reliable batteries to power a large modular capacitor bank for the electromagnetic railgun. They found their solution from K2 Energy Solutions Inc. in Henderson, Nev.

Officials of the Naval Sea Systems Command in Washington announced a potential $81.4 million contract to K2 Energy on Tuesday for the fully self-contained battery intermediate energy store system to power capacitor banks for the Navy's future electromagnetic railgun.

K2 Energy specializes in lithium iron phosphate battery technology -- a special kind of lithium battery that addresses the four major issues with current lithium technologies: safety, life, power, and environmental friendliness.

Navy leaders plan to use electromagnetic railguns aboard future surface warships to shoot non-explosive shells at a speed of Mach 8 -- eight times the speed of sound, or roughly 6,000 miles per hour. At that speed the weapon doesn not require explosives; the kinetic energy alone is enough to vaporize vehicle-size objects.

The Navy's electromagnetic railgun, under development by BAE Systems, requires staggering amounts of electricity to operate. The Navy envisions 64-megajoule electromagnetic railguns for future shipboard use.

The Office of Naval Research in Arlington, Va., has a functional 32-megajoule Electro-Magnetic Laboratory Rail Gun from BAE Systems, and operates it for research purposes at the Naval Surface Warfare Center in Dahlgren, Va.

The Navy's ability to deploy future electromagnetic railguns will hinge on producing the incredibly large amounts of electricity necessary to operate them. The 64 megajoules of power necessary to shoot the future electromagnetic railgun is equal to about 18 kilowatt hours, or about the same amount of power an average American household uses in an entire day.

Future warships carrying these kinds of weapons will need advanced power plants, and the requirement for electricity production is likely to have a profound influence over future ship design.

K2 Energy is involved in several advanced battery programs that help push the limits of the company's technology. The company is trying to develop an all-electric version of a Shelby Cobra high-performance sports car, for example.

The car, which company officials say will be faster and will have more power than the gasoline-powered Shelby Cobra will use high-performance K2 Energy 26650P cells with a 240-volt 300-horsepower electric engine that produces 1,000 pounds per foot of torque.

On this contract K2 Energy will do the work in Henderson, Nev., and should be finished by December 2016. For more information contact K2 Energy online at www.k2battery.com, or Naval Sea Systems Command at www.navsea.navy.mil.